EVAL5987 EVAL5987A 3 A step-down switching regulator demonstration board based on the L5987, L5987A Data brief Features 3 A DC output current 2.9 V to 18 V input voltage Output voltage adjustable from 0.6 V to 16 V 250 kHz switching frequency, programmable up to 1 MHz Internal soft-start and inhibit Low dropout operation: 100% duty cycle Zero-load current operation Overcurrent and thermal protection VFQFPN8 3 mm x 3 mm package or HSOP8 - V for the L5987A Description The compensation network on the demonstration The EVAL5987/A demonstration board provides board allows the use of MLCC as output filter to the design engineer with a fully functional step- keep the loop stable. The inductor saturation down switching regulator with an output current of current and forward current of the Schottky diode up to 3 A. The board integrates are within the current limit values. STMicroelectronics L5987/A step-down switching regulator, together with all the external The switching frequency on the demonstration components required for a typical application. board is set to 500 kHz by means of the R5 resistor connected to pin Fsw. The rated voltage of the input capacitor and the Schottky diode rectifier repetitive peak reverse voltage are both 25 V, making the board capable of covering the entire 2.9 V - 18 V input voltage range of the L5987/A device. The board features an external resistor divider (R1 and R2) designed for an output voltage of 1.8 V. The output voltage can be set to a level from 0.6 V up to the input voltage. November 2009 Doc ID 16613 Rev 1 1/6 For further information contact your local STMicroelectronics sales office. www.st.com 6EVAL5987/A application circuit and component list EVAL5987 - EVAL5987A 1 EVAL5987/A application circuit and component list Figure 1. Application circuit , U 3 ( - 3 6 6 N 6I 6 T U 6O 6 4 U U N ( 9 . 3 ( 6 6 6 , 03 34 7 -0 / 2 2 2 + K H & + 2 2 P & N & K - V Figure 2. Package - V Table 1. Component list Reference Part number Description Manufacturer C1 GRM32ER61E226KE15 22 F, 25 V Murata C2 GRM32ER61E226KE15 22 F, 25 V Murata C3 2.2 nF, 50 V C4 10 nF, 50 V C5 330 pF, 50 V C6 220 nF, 25 V R1 4.99 k , 1%, 0.1 W 0603 R2 2.49 k , 1%, 0.1 W 0603 R3 330 , 1%, 0.1 W 0603 R4 2 k , 1%, 0.1 W 0603 R5 100 k, 1%, 0.1 W 0603 L1 MSS1038-522NL 5.2 H, 30%, 5.28 A Coilcraft D1 STPS2L25V 2 A, 25 V STMicroelectronics 2/6 Doc ID 16613 Rev 1 (3/0 EXPOSED PAD 6&1&0. X MM &3 . , ). /5